Connectors for railcars are usually attached to each end of a car underside within the car center sill. A convex end of the connector normally rests against a follower block held within a sill pocket casting that is mounted within the sill to withstand forces tending to thrust the connector into the sill - e.g. compressive or buff loading. Additionally the connector is held against being withdrawn from the sill by a pin or drawbar or by a collar which is spaced from the follower block. When the connector is first assembled to the car the clearances between the aforementioned parts are minimal and there is virtually no slack or movement of the parts longitudinal of the car when the forces on the connector are reversed as occurs each time the car is accelerated or decelerated. However, wear occurs through use causing spaces to be created between the parts. Such spaces are known as slack and the cumulative effect will be to repeat and magnify impact forces upon acceleration and deceleration. One cure for this problem has been to include a wedge shaped shim between two of the parts, usually between the follower block and the closed end of the sill pocket casting as shown in U.S. Pat. Nos. 3,716,146, 4,456,133, 4,549,666 and 4,593,829.
One or both of the adjacent surfaces of the follower block and/or the pocket casting are sloped to correspond to the wedge. The result is that as wear occurs and spaces increase the wedge will move downward by gravity to separate the adjacent parts sufficiently to take up the slack. However, at some point the wear may exceed the ability of the wedge to compensate and it must be replaced or augmented. But heretofore there has been no means to visually gauge the extent of wear and anticipate the need for replacement.
Also there are occasions when connectors must be disassembled from railcars to permit maintenance. At such times the wedge must be separated from the adjacent parts to create sufficient slack to enable the parts to be removed from the sill. But heretofore this has required the insertion of tools through ports in the sill and/or pocket casting to engage and lift the wedge.
Furthermore, as the parts wear, the wedge may rotate or shift within the pocket resulting in poor performance. Moreover in some installations the connector is rotatable within the pocket casting so as to permit a railcar to be rotated for rapid dumping, in which case the parts become inverted and the wedge may unintentionally become dislodged by gravity.